Information recording medium, integrated circuit, recording/playback apparatus, computer program, and information recording/playback method

ABSTRACT

An optical disk  101  in which information is recorded on a groove track, and an optical disk  107  in which information is recorded on a land track. The optical disk  101  has a control data area  102,  and a data recording area  103  in which user data is recorded. The optical disk  107  has a control data area  108,  and a data recording area  109  in which user data is recorded. A code for indicating the groove track or the land track onto which a tracking servo control is to be executed is provided both in the control data area  102  of the optical disk  101,  and in the control data area  108  of the optical disk  107.

This application is a Divisional of application Ser. No. 11/547,398filed Oct. 2, 2006, which is the National Stage of InternationalApplication No. PCT/JP2005/012453, filed Jul. 6, 2005.

TECHNICAL FIELD

The present invention relates to a technology of determining a trackingpolarity in playback of optical information recorded in an informationrecording medium.

BACKGROUND ART

In recent years, research and development on high-density optical diskshave been active, and DVD has been commercially available. Thus, theoptical disks have been establishing their positions as importantinformation recording media. Conventionally, development on DVDexclusively for playback use has been active among a variety of DVDstandards. However, as DVD recorders are spread, development onrecordable DVD has been progressed. Further, a recent trend proposes aBlu-ray rewritable disk (BD-RE) as a result of pursuing furtherhigh-density optical disks. Thus, the BD-RE has also been available, andused in recording of digital broadcasting contents or the like.

There are known two methods of forming a recording layer in aninformation recordable optical disk, namely, vapor deposition and spincoating, as disclosed in Japanese Unexamined Patent Publication No.2003-109246, for instance. These two recording layer forming methods aredescribed referring to FIGS. 13A and 13B.

FIG. 13A and 13B are cross-sectional views each showing an optical disk.FIG. 13A shows an example of a BD-RE, wherein a recording layer made ofa phase change material is formed by vapor deposition. FIG. 13B shows anexample of a DVD-R, wherein a recording layer made of anorganic-pigment-based material is formed by spin-coating.

As shown in FIG. 13A, the BD-RE is produced by forming a reflectinglayer 502 on an injection-molded base member 501 by sputtering or a liketechnique, forming a recording layer 503 on the reflecting layer 502 byvapor deposition, and attaching a sheet member 505 to the recordinglayer 503 with an adhesive layer 504 being formed between the recordinglayer 503 and the sheet member 505. Assuming that a portion of anasperity on each layer including the base member 501, which is formed onthe side of the disk where an optical pickup device for emitting laserlight is arranged, is called as a “groove track”, and a portion of theasperity on each layer, which is formed on the side of the disk oppositeto the side where the optical pickup device is arranged, is called as a“land track”, information is recorded on the groove track.

As shown in FIG. 13B, a base member 506 and a base member 510 eachproduced by injection molding are attached to each other via an adhesivelayer 509 by spin-coating. Prior to the attachment of the base members506 and 510, a recording layer 507 is formed on the base member 506 byspin-coating, and a reflecting layer 508 is formed on the recordinglayer 507 by sputtering or a like technique. Similarly to the disk asshown in FIG. 13A, assuming that a portion of an asperity on the basemember 506, which is formed on the side of the disk where an opticalpickup device for emitting laser light is arranged, is called as a“groove track”, and a portion of the asperity on the base member 506,which is formed on the side of the disk opposite to the side where theoptical pickup device is arranged, is called as a “land track”,information is recorded in the groove track.

To realize high-density recording in the BD-RE as shown in FIG. 13A,laser light of a shorter wavelength than the one used for an ordinaryDVD is used, and an objective lens having a high numerical aperture (NA)is used. In view of this, in the BD-RE as shown in FIG. 13A, laser lightis emitted from the side of the sheet member 505 having a smallerthickness than the base member 501, in place of being emitted from theside of the base member 506, as in the DVD-R having the asperity patternas shown in FIG. 13B.

The spin-coating technique is advantageous in shortening the timerequired for forming a recording layer. Applying this technique inproducing a BD may result in a construction as shown in FIG. 13C.Specifically, as shown in FIG. 13C, a BD is produced by forming areflecting layer 512 on an injection-molded base member 511 bysputtering or a like technique, forming a recording layer 513 on thereflecting layer 512 by spin-coating, and attaching a sheet member 515to the recording layer 513, with an adhesive layer 514 being formedbetween the recording layer 513 and the sheet member 515. In the BD asshown in FIG. 13C, assuming that a portion of an asperity on each layerincluding the base member 511, which is formed on the side of the diskwhere an optical pickup device for emitting laser light is arranged, iscalled as a “groove track”, and a portion of the asperity on each layer,which is formed on the side of the disk opposite to the side where theoptical pickup device is arranged, is called as a “land track”, it isdesirable to record information on the land track.

In other words, since the recording layer 513 is required to have acertain thickness, the recording layer 513 is required to have a largethickness as shown in FIG. 13D if information is to be recorded on thegroove track, with the result that a material cost of the disk as shownin FIG. 13D is increased, as compared with the disk as shown in FIG.13C.

A BD-RE of a type in which information is recorded on a groove track, asshown in FIG. 13A, is well known. Under the circumstances that there aretwo types of disks, wherein one type of disk is such that information isrecorded on a groove track, and the other type of disk is such thatinformation is recorded on a land track, a recording/playback apparatushas difficulty in readily judging whether the disk is of a type having aconfiguration that information has been or is to be recorded on the landtrack or on the groove track, with the result that it takes a certaintime to start up the recording/playback apparatus.

BRIEF SUMMARY OF THE INVENTION

In view of the above problems residing in the prior art, an object ofthe invention is to provide an information recording medium such as adisk that enable to suppress the time required for startup of arecording/playback apparatus from unduly increasing in case ofinformation recording or information playback in or out of a diskconstructed such that information is to be or has been recorded in agroove track, and a disk constructed such that information is to be orhas been recorded in a land track.

To accomplish the above object, an aspect of the invention is directedto an information recording medium comprising a data recording area anda control data area, and having a construction that information isrecorded on a groove track or on a land track of a recording layer ofthe data recording area and the control area, wherein the informationrecording medium has a code for indicating the groove track or the landtrack onto which tracking servo control is executed.

The above arrangement enables to promptly determine whether the trackingservo control is executed onto the groove track or onto the land trackwhen the information recording medium is loaded in a recording/playbackapparatus, thereby keeping the time required for startup of theapparatus from unduly increasing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view of an optical disk as an example of aninformation recording medium embodying the invention.

FIG. 1B is a plan view of an optical disk as another example of theinformation recording medium embodying the invention.

FIG. 1C is a cross-sectional view of the optical disk shown in FIG. 1A.

FIG. 1D is a cross-sectional view of the optical disk shown in FIG. 1B.

FIG. 2A is a cross-sectional view partially showing an optical diskconstructed such that information is recorded on a groove track.

FIG. 2B is a cross-sectional view partially showing an optical diskconstructed such that information is recorded on a land track.

FIG. 3 is a plan view schematically and enlargedly showing tracks in adata recording area of an optical disk embodying the invention.

FIG. 4 is an illustration for explaining an altered wobbling pattern ofan optical disk embodying the invention.

FIGS. 5A and 5B are illustrations for explaining altered wobblingpatterns of an optical disk embodying the invention.

FIG. 6 is a plan view schematically and enlargedly showing tracks in acontrol data area of an optical disk embodying the invention.

FIG. 7 is an illustration conceptually showing addresses.

FIG. 8 is a block diagram of a recording/playback apparatus embodyingthe invention.

FIG. 9 is an illustration for explaining playback signals in therecording/playback apparatus of the invention.

FIG. 10 is a block diagram of an integrated circuit embodying theinvention.

FIG. 11 is a plan view of an optical disk as another example of theinformation recording medium embodying the invention.

FIG. 12 is a block diagram of a recording/playback apparatus embodyingthe invention.

FIG. 13A is a cross-sectional view of a conventional optical diskproduced by vapor deposition.

FIG. 13B is a cross-sectional view of a conventional optical diskproduced by spin-coating.

FIG. 13C is a cross-sectional view of an optical disk produced byspin-coating.

FIG. 13D is a cross-sectional view of an optical disk produced byspin-coating.

BEST NODE FOR CARRYING OUT THE INVENTION

In the following, preferred embodiments of the invention are describedreferring to the drawings. FIGS. 1A and 1B respectively show an opticaldisk 101 and an optical disk 107 as examples of an information recordingmedium embodying the invention. FIG. 1A and FIG. 1C each shows theoptical disk 101 of a recordable type constructed such that informationis recorded on a groove track. FIG. 1A is a plan view, and FIG. 1C is across-sectional view as viewed from a circumferential direction of theoptical disk 101. An example of the optical disk 101 is a BD-RE. FIG. 1Band FIG. 1D each shows the optical disk 107 of a recordable typeconstructed such that information is recorded on a land track. FIG. 1Bis a plan view, and FIG. 1D is a cross-sectional view as viewed from acircumferential direction of the optical disk 107. An example of theoptical disk 107 is a DVD-R. The track may be concentrically formed orspirally formed.

As shown in FIG. 1A, the optical disk 101 has a control data area 102,and a data recording area 103 which is provided on a radially outerregion relative to the control data area 102. The radius of the controldata area 102 is defined by the disk standard, and information such asadministration data relating to administration of the disk has beenpre-recorded in the control data area 102. The radius of the datarecording area 103 is also defined by the disk standard. The datarecording area 103 is an area in which data is recorded by a user.

The optical disk 101 shown in FIG. 1A has a layer construction such thata base member 201, a reflecting layer 202, a recording layer 203, anadhesive layer 204, and a sheet member 205 are formed one over the otherin this order, as shown in FIG. 1C. The optical disk 101 is produced byforming the reflecting layer 202 on the injection-molded base member 201by sputtering or a like technique, forming the recording layer 203 onthe reflecting layer 202 by vapor deposition, and attaching the sheetmember 205 to the recording layer 203, with the adhesive layer 204 beingformed between the recording layer 203 and the sheet member 205. Thus,the optical disk 101 is produced.

Asperities are formed on the base member 201. Likewise, asperities areformed on the recording layer 203 in accordance with the asperitypattern on the base member 201. Assuming that a portion of an asperityon each layer including the base member 201, which is formed on the sideof the optical disk 101 where an optical pickup device for emittinglaser light is arranged, is called as a “groove track”, and a portion ofthe asperity on each layer, which is formed on the side of the opticaldisk 101 opposite to the side where the optical pickup device isarranged, is called as a “and track”, information is recorded on agroove track 104 of the recording layer 203, as shown in FIG. 2A.

As shown in FIG. 1B, the optical disk 107 has a control data area 108,and a data recording area 109 which is provided on a radially outerregion relative to the control data area 108. The radius of the controldata area 108 is defined by the disk standard, and data such asadministration data relating to administration of the disk has beenpre-recorded in the control data area 108. The radius of the datarecording area 109 is also defined by the disk standard. The datarecording area 109 is an area in which data is recorded by a user.

The optical disk 107 shown in FIG. 1B has a layer construction such thata base member 211, a reflecting layer 212, a recording layer 213, anadhesive layer 214, and a sheet member 215 are formed one over the otherin this order, as shown in FIG. 1D. The optical disk 107 is produced byforming the reflecting layer 212 on the injection-molded base member 211by sputtering or a like technique, forming the recording layer 213 onthe reflecting layer 212 by spin-coating, and attaching the sheet member215 to the recording layer 213, with the adhesive layer 214 being formedbetween the recording layer 213 and the sheet member 215. Thus, theoptical disk 107 is produced.

Asperities are formed on the base member 211. Likewise, asperities areformed on the lower surface of the recording layer 213 in accordancewith the asperity pattern of the base member 211. In other words, theoptical disk 107 is constructed in such a manner that a small thicknessportion and a large thickness portion of the recording layer 213 arealternately formed in a radial direction of the disk. Assuming that aportion of an asperity on each layer including the base member 211,which is formed on the side of the optical disk 107 where an opticalpickup device for emitting laser light is arranged, is called as a“groove track”, and a portion of the asperity on each layer, which isformed on the side of the optical disk 107 opposite to the side wherethe optical pickup device is arranged, is called as a “land track”,information is recorded on a land track 110 of the recording layer 213,as shown in FIG. 2B.

The optical disk 107 has the arrangement that the recording layer 213 isformed by spin-coating, and that information is recorded on the landtrack 110. This arrangement enables to shorten the time required forforming the recording layer 213, to perform stable informationrecording, and to keep the material cost of the optical disk from undulyincreasing.

Next, the embodiment of the invention is described referring to FIG. 3.Denoted by the reference numeral 2001 in the uppermost section of FIG. 3is an enlarged illustration of a region 105 (see FIG. 1A) of the groovetrack 104 of the data recording area 103 in a track direction of theoptical disk 101. Likewise, denoted by the reference numeral 2002 inFIG. 3 is an enlarged illustration of a region 111 (see FIG. 1B) of theland track 110 of the data recording area 109 in a track direction ofthe optical disk 107. As shown by the patterns 2001 and 2002, the groovetrack 104 and the land track 110 are wobbled, and information such as async pattern, address information, and information relating to a starttiming of recording user data is recorded in the format of the wobblingpattern.

Let's assume that the same information (e.g., address information) hasbeen recorded on the groove track 104 of the optical disk 101 and in theland track 110 of the optical disk 107. Then, as shown FIG. 3, thewobbling pattern 2001 of the groove track 104 in the optical disk 101,and the wobbling pattern 2002 of the land track 110 in the optical disk107 are different from each other by 180 degrees in phase. In otherwords, the wobbling directions of tracks are opposite to each other withrespect to the direction of playback between an information recordingmedium constructed such that data is recorded on a groove track, and aninformation recording medium constructed such that data is recorded on aland track.

Differential signals to be detected are inverted between a case ofemitting laser light onto a groove track, and a case of emitting laserlight onto a land track. In view of this, by making the wobblingdirection of the groove track 104 in the optical disk 101, and thewobbling direction of the land track 110 in the optical disk 107opposite to each other, the polarity of a differential signal to bedetected in playback of data from the groove track 104 in the opticaldisk 101, and the polarity of a differential signal to be detected inplayback of data from the land track 110 in the optical disk 107 can bemade coincident with each other. In this arrangement, even with use of arecording/playback apparatus which is merely compatible with an opticaldisk having a configuration that information is recorded on a groovetrack such as the optical disk 101, an address of an optical disk havinga configuration that information is recorded on a land track such as theoptical disk 107 can be detected in accordance with the same sequence asthe optical disk 101, as far as tracking servo control is executableonto the land track. The differential signal means a difference inoutput signals from two light receiving areas of a photo-detector in thecase where reflected light from the optical disk has been received onthe photo-detector, wherein the two light receiving areas are obtainedby dividing the light receiving plane of the photo-detector into twohalved parts along an imaginary line parallel with a tangential line ofthe track direction.

As shown in FIG. 3, the wobbling pattern 2001 in the region 105 of thegroove track 104 is constituted of patterns A and patterns B. Thepattern B wobbles with a frequency 1.5 times as high as the frequency ofthe pattern A. The pattern B appears between the two adjacent patternsA. Likewise, the wobbling pattern 2002 in the region 111 of the groovetrack 110 is constituted of patterns C and patterns D. The pattern Dwobbles with a frequency 1.5 times as high as the frequency of thepattern C. The pattern D appears between the two adjacent patterns C.Whereas the wobbling pattern 2001 in the region 105 and the wobblingpattern 2002 in the region 111 are different from each other by 180degrees in phase, the frequencies of the pattern A and the pattern C areidentical to each other, and a frequency component included in thepattern B is the same as a frequency component included in the patternD.

Address information and the like are recorded on the groove track 104 ofthe optical disk 101 with use of the pattern A and the pattern B. Forinstance, a pattern arrangement such as the wobbling pattern 2003, whichis constituted of the pattern B, followed by appearance of the pattern Athree times, and then the pattern B, is defined as a value “0”, and apattern arrangement such as the wobbling pattern 2004, which isconstituted of the pattern B, followed by appearance of the pattern Atwo times, and then the pattern B, is defined as a value “1”. In thisway, address information and the like are constituted of a combinationof the values “0” and “1”.

Likewise, address information and the like are recorded on the landtrack 110 in the optical disk 107 with use of the pattern C and thepattern D. For instance, a pattern arrangement such as the wobblingpattern 2005, which is constituted of the pattern D, followed byappearance of the pattern C three times, and then the pattern D, isdefined as a value “0”, and a pattern arrangement such as the wobblingpattern 2006, which is constituted of the pattern D, followed byappearance of the pattern C two times, and then the pattern D, isdefined as a value “1”.

Regarding the groove track 104, the time required for detecting asucceeding pattern B after detection of a preceding pattern B is shorterin the wobbling pattern 2004 identified by the value “1”, than in thewobbling pattern 2003 identified by the value “0”. Also, regarding theland track 110, the time required for detecting a succeeding pattern Dafter detection of a preceding pattern D is shorter in the wobblingpattern 2006 identified by the value “1” than in the wobbling pattern2005 identified by the value “0”. Furthermore, as mentioned above, sincethe frequencies of the pattern A and the pattern C are identical to eachother, and the frequency components included in the pattern B and in thepattern D are the same, the following idea is proposed. If a playbackapparatus is capable of detecting the pattern B and the pattern D, theplayback apparatus can detect the value “0” based on the wobblingpatterns 2003 and 2005, and can detect the value “1” based on thewobbling patterns 2004 and 2006, regardless of the polarity of thedetected differential signal. In this way, the playback apparatus candetect information constituted of the combination of the values “0” and“1”.

As far as the wobbling pattern in the groove track 104 and the wobblingpattern in the land track 110 are different from each other by 180degrees in phase, the wobbling pattern may include a pattern other thanthe patterns A through D. Further alternatively, the wobbling pattern inthe groove track (land track) may be constituted of a combination of twoor more patterns.

As far as a time lag in appearance of predetermined patterns can bedetected by utilizing the values “0” and “1”, the manner of defining thevalues “0” and “1” is not limited to the foregoing.

Further, as far as information detected from the groove track 104 of theoptical disk 101 can be detected from the land track 110 of the opticaldisk 107 in the case where the same information is recorded on thegroove track 104 and on the land track 110, the manner of changing thepattern of the track, and the manner of defining the values “0” and “1”are not specifically limited to the foregoing.

For instance, as shown in FIG. 4, it is possible to adopt a wobblingpattern, wherein a pattern corresponding to a predetermined number ofcycles of time, e.g., 3 cycles of time is wobbled with respect to amonotonous reference waveform. In the example of FIG. 4, the first cycleof time, and the third cycle of time are ⅔ times as long as the cycle Tof time of the reference waveform, and the second cycle of time is thesame as the cycle T of time of the reference waveform. In such analtered arrangement, the wobbling directions may be made opposite toeach other between an optical disk having a configuration thatinformation is recorded on a groove track, and an optical disk having aconfiguration that information is recorded on a land track.

Further alternatively, it is possible to adopt wobbling patterns asshown in FIGS. 5A and 5B, wherein a saw-tooth waveform is used in placeof a monotonous reference waveform such as a sinusoidal waveform. Asaw-tooth waveform is obtained by combination of a sine wave and acosine wave, for instance. As shown in FIG. 5A, it is possible to make apattern E, wherein the peak point of the pattern E is displaced in abackward direction in time relative to the peak point of a referencewaveform at the time of playback by adding a sine wave to a cosine wave,and to define the pattern E as the value “1”. Likewise, as shown in FIG.5A, it is possible to make a pattern F, wherein the peak point of thepattern F is displaced in a forward direction in time relative to thepeak point of the reference waveform at the time of playback bysubtracting a sine wave from a cosine wave, and to define the pattern Fas the value “0”. In this way, the wobbling pattern as shown in FIG. 5Ais obtained by combination of the pattern E and the pattern F. On theother hand, the wobbling direction (e.g., starting direction of wobblewith respect to reproduction direction) of the wobbling pattern as shownin FIG. 5B is opposite to the wobbling direction of the wobbling patternas shown in FIG. 5A. Specifically, the wobbling pattern as shown in FIG.5B is constituted of a pattern G corresponding to the pattern E, and apattern H corresponding to the pattern F. The wobbling pattern as shownin FIG. 5A may be adopted in an optical disk having a configuration thatinformation is recorded on a groove track, and the wobbling pattern asshown in FIG. 5B may be adopted in an optical disk having aconfiguration that information is recorded on a land track to therebymake the wobbling directions of the tracks of the optical disks oppositeto each other. In such an arrangement, the wobbling direction at aleading portion of wobbling in the optical disk 101 having aconfiguration that information is recorded on a groove track lies on aradially inner side of the optical disk 101, whereas the wobblingdirection at a leading portion of wobbling in the optical disk 107having a configuration that information is recorded on a land track lieson the radially outer side of the optical disk 107. The term “leadingportion of wobbling” means a leading portion of a series of wobblingpatterns constituting certain data.

Next, the embodiment of the invention is described referring to FIG. 6.Denoted by the reference numeral 3001 in FIG. 6 is an enlargedillustration of a region 106 (see FIG. 1A) of a groove track in thecontrol data area 102 in the track direction of the optical disk 101.Likewise, denoted by the reference numeral 3002 in FIG. 6 is an enlargedillustration of a region 112 (see FIG. 1B) of a land track in thecontrol data area 108 in the track direction of the optical disk 107.

As shown in FIG. 6, the groove track in the control data area 102 of theoptical disk 101, and the land track in the control data area 108 of theoptical disk 107 are modulated, respectively.

The groove track in the control data area 102 of the optical disk 101 ismodulated with use of two patterns, as shown by the wobbling pattern3001. Specifically, in one of the two patterns, the polarity is notinverted in a basic cycle T2 of time, whereas in the other one of thetwo patterns, the polarity is inverted in a basic cycle T2 of time. Thepolarity is inverted in both of the two patterns every basic cycle T2 oftime. The pattern in which the polarity is not inverted is defined asthe value “0”, and the pattern in which the polarity is inverted isdefined as the value “1”.

Likewise, the land track in the control data area 108 of the opticaldisk 107 is modulated with use of two patterns, as shown by the wobblingpattern 3002. Specifically, in one of the two patterns, the polarity isnot inverted in a basic cycle T2 of time, whereas in the other one ofthe two patterns, the polarity is inverted in a basic cycle T2 of time.The polarity is inverted in both of the two patterns every basic cycleT2 of time. The pattern in which the polarity is not inverted is definedas the value “0”, and the pattern in which the polarity is inverted isdefined as the value “1”.

In this arrangement, as far as a playback apparatus can detect a changeof the polarity, the values “0” and “1” can be detected regardless ofthe polarity of the detected differential signal, and information suchas administration data, address information, and a sync pattern, each ofwhich is constituted of combination of the values “0” and “1” can bedetected.

As shown in FIG. 7., which is a conceptual illustration of addresses,for instance, these information are recorded by allowing the individualinformation to be stored in a predetermined address allocated in a trackof the control data area 102 (108). For instance, informationrepresenting the type of the disk is recorded in the address 301, andinformation representing the storage capacity of the disk is recorded inthe address 302. Various information including the aforementionedinformation are repeatedly recorded in plural addresses. For instance,the information representing the type of the disk is recorded in theaddress 311, as well as in the address 301, and the informationrepresenting the storage capacity of the disk is recorded in the address312, as well as in the address 302.

A code is provided in the track of the control data area 102 (108) forindicating the groove track or the land track onto which tracking servocontrol is executed. The code is provided both in the control data area102 of the optical disk 101, and in the control data area 108 of theoptical disk 107. In the optical disk 101 (107), the code is recorded inthe addresses 303 and 313, for instance. The code is identificationinformation recorded in the optical disk 101 (107) in such a manner thatan optical disk having a code of a value “0”, for instance, representsan optical disk having a configuration that tracking servo control isexecuted onto the groove track, and that an optical disk having a codeof a value “1”, for instance, represents an optical disk having aconfiguration that tracking servo control is executed onto the landtrack. The playback apparatus embodying the invention is configured insuch a manner that judgment as to whether tracking servo control isexecuted onto the land track or onto the groove track is made byreproducing the identification information recorded in the optical disk.The construction of the playback apparatus will be described later indetail.

Referring back to FIG. 6, let's assume that the same information isrecorded on the groove track of the control data area 102 of the opticaldisk 101 and on the land track of the control data area 108 of theoptical disk 107. Then, the direction of modulation of the groove trackin the optical disk 101, and the direction of modulation of the landtrack in the optical disk 107 are different from each other by 180degrees in phase. In other words, directions of starting modulation ofthe track are opposite to each other with respect to the playbackdirection between an information recording medium having a configurationthat data is recorded on a groove track, and an information recordingmedium having a configuration that data is recorded on a land track. Forinstance, whereas the optical disk 101 having a configuration that datais recorded on a groove track has a feature that the direction ofmodulation in a modulation start portion of the track lies on a radiallyinner side of the optical disk 101, the optical disk 107 having aconfiguration that data is recorded on a land track has a feature thatthe direction of modulation in a modulation start portion of the tracklies on the radially outer side of the optical disk 107. The term“modulation start portion” indicates a leading portion of a series ofmodulated track portions constituting certain data.

Differential signals to be detected are inverted between a case ofemitting laser light onto a groove track, and a case of emitting laserlight onto a land track. In view of this, by making the direction ofmodulation in the modulation start portion of the land track, and thedirection of modulation in the modulation start portion of the groovetrack opposite to each other, the polarity of a differential signal tobe detected in playback of data from the groove track in the controldata area 102 of the optical disk 101, and the polarity of adifferential signal to be detected in playback of data from the landtrack in the control data area 108 of the optical disk 107 can be madecoincident with each other. In this arrangement, even with use of arecording apparatus which is merely compatible with an optical diskhaving a configuration that data is recorded in a groove track such asthe optical disk 101, administration data and the like of an opticaldisk having a configuration that data is recorded in a land track suchas the optical disk 107 can be detected in accordance with the samesequence as the optical disk 101, as far as tracking servo control isexecutable onto the land track.

In the foregoing embodiment of the invention, the groove track in thecontrol data area 102, and the land track in the control data area 108are modulated. Alternatively, the groove track in the control data area102 and the land track in the control data area 108 may be wobbled, orthe groove track in the control data area 102 and the land track in thecontrol data area 108 may have asperities in a thickness direction ofthe optical disk 101 (107).

Further, as far as information detected from the groove track in thecontrol data area 102 can be detected from the land track in the controldata area 108 in the case where the same information is recorded in thegroove track of the control data area 102 and in the land track of thecontrol data area 108, the manner of changing the pattern of the track,and the manner of defining the values “0” and “1” are not specificallylimited to the foregoing.

Next, the embodiment of the invention is described referring to FIG. 8.FIG. 8 is a block diagram schematically showing a recording/playbackapparatus embodying the invention. The recording/playback apparatuscomprises an optical head 402, a first signal detecting section 404serving as signal detecting means A, a first pattern detecting section406 serving as pattern detecting means A, a head moving section 408serving as head moving means, a code detecting section 425 serving as acode detector, a tracking polarity switching section 414 serving as atracking polarity switcher, and a tracking controlling section 416serving as a tracking servo controller. In the present specification,the recording/playback apparatus means an apparatus which performs atleast one of recording of information into a land track or into a groovetrack of a recording layer of an information recording medium, andplayback of information recorded in the land track or in the groovetrack.

The optical head 402 records information into the optical disk 401 orplays back information recorded on the optical disk 401 by emittinglight onto an optical disk 401 or by receiving reflected light from theoptical disk 401.

The code detecting section 425 controllably acquires informationincluded in the code in response to tracking servo control based on apredetermined polarity, namely, a tracking polarity which represents aland track or a groove track. The code detecting section 425functionally includes a second signal detecting section 410 serving assignal detecting means B, and a second pattern detecting section 412serving as pattern detecting means B. The second signal detectingsection 410 receives a differential signal 403 from the optical head 402under the tracking servo control, and generates a binary signal 411 inresponse to a change of the polarity of the differential signal 403. Thesecond pattern detecting section 412 discriminates the code based on thebinary signal 411 sent from the second signal detecting section 410, andoutputs a signal 413 based on the discriminated code.

The tracking polarity switching section 414 receives the signal 413 fromthe second pattern detecting section 412, and outputs a signal 415indicative of whether the tracking polarity is to be switched over basedon the signal 413.

In this section, a case is described in which the optical disk 107having a configuration that data is recorded on a land track is adoptedas the optical disk 401. The optical head 402 travels to a certainposition in a radial direction on the optical disk 401 by the headmoving section 408, and executes tracking servo control onto a groovetrack of the optical disk 401 by the tracking controlling section 416.In this embodiment, tracking servo control is executed onto a groovetrack for the first time when the optical disk 401 is loaded as aninitial setting. Alternatively, tracking servo control may be executedonto a land track for the first time when the optical disk is loaded.

The tracking controlling section 416 executes tracking servo control bymonitoring a signal 418 sent from the optical head 402. The signal 418is a signal component in a low frequency band of a differential signaloutputted from two light receiving areas of a photo-detector in the casewhere reflected light from the groove track in the optical disk 401 hasbeen received on the photo-detector, wherein the two light receivingareas are obtained by dividing the light receiving plane of thephoto-detector into two halved parts along an imaginary line parallelwith a tangential line of the track direction.

The optical head 402 outputs, to the first signal detecting section 404,a differential signal 403 obtained based on reflected light from thegroove track in the data recording area 109. The differential signal 403indicates a difference in output signals from the two light receivingareas of the photo-detector in the case where reflected light from thegroove track in the data recording area 109 is received on thephoto-detector, wherein the two light receiving areas are obtained bydividing the light receiving plane of the photo-detector into two halvedparts along the imaginary line parallel with the tangential line of thetrack direction.

Let's assume that a waveform as shown by the reference numeral 6002 inFIG. 9 is detected by the first signal detecting section 404 when theoptical head 402 is driven to playback data from a land track in thedata recording area 109. When tracking servo control is executed onto agroove track adjoining the land track, the first signal detectingsection 404 detects a waveform 6001 as shown in FIG. 9 if a crosstalkeffect from the other one of the land tracks adjoining the groove trackis significantly small. The first signal detecting section 404discriminates whether a detected pattern represents the value “0” or “1”based on a time lag between a timing of detecting a preceding patternhaving the same frequency component as the pattern B, and a timing ofdetecting a succeeding pattern having the same frequency component asthe pattern B. The first signal detecting section 404 generates a binarysignal 405 representing a wobbling pattern based on the discriminatedvalue “0” or “1”, and outputs the binary signal 405 to the first patterndetecting section 406.

Upon receiving the binary signal 405, the first pattern detectingsection 406 extracts an address component from the binary signal 405,and outputs the address component as a signal 407 to the head movingsection 408. The head moving section 408 acquires a travel distance ofthe optical head 402 based on the signal 407 and on the current address,and outputs a signal 409 to move the optical head 402 to a designatedposition on the control data area 108 based on the travel distance.

The optical head 402, when moved to the designated position on thecontrol data area 108, outputs, to the second signal detecting section410, a differential signal 403 obtained based on the reflected lightfrom the groove track in the optical disk 107. The differential signal403 indicates a difference in output signals from the two lightreceiving areas of the photo-detector in the case where reflected lightfrom the groove track in the control data area 108 is received on thephoto-detector, wherein the two light receiving areas are obtained bydividing the light receiving plane of the photo-detector into two halvedparts along the imaginary line parallel with the tangential line of thetrack direction.

Let's assume that a waveform indicated by the reference numeral 6004 inFIG. 9 is detected by the second signal detecting section 410 in thecase where the optical head 402 is driven to playback data from a landtrack in the control data area 108. When tracking servo control isexecuted onto a groove track adjoining the land track, the second signaldetecting section 410 detects a waveform 6003 as shown in FIG. 9 if acrosstalk effect from the other one of the land tracks adjoining thegroove track is significantly small. The second signal detecting section410 discriminates whether a detected pattern represents the value “0” or“1” by detecting a change in polarity of the differential signal 403.The second signal detecting section 410 generates a binary signal 411based on the discriminated value “0” or “1”, and outputs the binarysignal 411 to the second pattern detecting section 412.

The second pattern detecting section 412 detects a code for determiningthe tracking polarity based on the binary signal 411, and outputs, tothe tracking polarity switching section 414, a signal 413 indicatingthat the tracking polarity represents a land track.

The tracking polarity switching section 414 compares the signal 413 withthe current tracking polarity. In this embodiment, the optical head 402is designed to execute tracking servo control onto a groove track priorto a land track. Accordingly, in this state, the tracking polarityswitching section 414 outputs, to the tracking controlling section 416,a signal 415 requesting changeover of the tracking polarity, so thattracking servo control be executed onto the land track. Upon receivingthe signal 415, the tracking controlling section 416 outputs a signal417 to change over the tracking servo control from the groove track tothe land track, and executes tracking servo control onto the land trackby monitoring the signal 418.

In this embodiment, the optical head 402 travels to the control dataarea 108 after detecting address information from the data recordingarea 109 one time. Alternatively, the optical head 402 may graduallytravel to the control data area 108 while cyclically detecting addressinformation from the data recording area 109, or may directly travel tothe control data area 108 immediately after the optical disk is loaded.

Further alternatively, it is possible to reproduce the code again afterchangeover of the tracking polarity to confirm whether the currentlydetected tracking polarity is proper.

In this embodiment, the code is provided to judge whether tracking servocontrol is executed onto the groove track or onto the land track in thecontrol data area. Alternatively, it is possible to provide a codehaving the same function as the above code in the track(s) constitutingthe data recording area in place of the above code or in addition to theabove code. Providing the code in the data recording area contributes toincrease of a detecting ratio of the code, because the code is providedin a relatively large area, as compared with the arrangement that thecode is provided in the control data area, whereby playback operation iseasily carried out.

Further, in this embodiment, the optical disk has a single recordinglayer. Alternatively, the optical disk may have plural recording layers.In such an altered arrangement, preferably, the code may be provided ineach of the recording layers.

There is a case that recording conditions such as the intensity or theposition of a recording pulse are recorded in the control data area. Insuch a case, it is desirable to provide the code for determining whethertracking servo control is executed onto the groove track or onto theland track at a forward position in a playback direction relative to thearea where the recording conditions have been recorded. This arrangementenables to promptly determine the tracking polarity in the case whereplayback is exclusively required, thereby shortening the time requiredfor starting the playback operation.

In this embodiment, a recordable optical disk has been described as anexample of the inventive information recording medium. Alternatively, arewritable optical disk may be an example of the inventive informationrecording medium.

In this embodiment, the first signal detecting section 404 discriminatesthe values “0” and “1” based on a time lag between a timing of detectinga preceding pattern having the same frequency component as the patternB, and a timing of detecting a succeeding pattern having the samefrequency component as the pattern B. Alternatively, it is possible toextract an output signal solely from one of the two light receivingareas of the photo-detector closer to the land track from which data isto be played back, as the signal 403, in place of using a differentialsignal, in the case where a crosstalk effect from an adjoining landtrack is significantly large, and it is difficult to detect a binarysignal, address information, a sync pattern or the like within apredetermined time, or within a predetermined area, or within apredetermined retry processing.

Further, if it is difficult to detect a binary signal, addressinformation, a sync pattern or the like within a predetermined time, orwithin a predetermined area, or within a predetermined retry processingin a case other than the case of code detection, it may be possible toallow the code detecting means to output a signal requesting changeoverof the tracking polarity to the tracking polarity switching section 414.A code for clearly indicating the tracking polarity may be omitted inthe optical disk if an arrangement other than the arrangement that thecode is detected is adopted.

Further alternatively, it is possible to directly detect a change of adifferential signal, and to allow the tracking polarity switchingsection 414 to receive a signal requesting changeover of the trackingpolarity if the change is out of a predetermined range. In such analtered arrangement, since there is no need of detecting a code, a codefor clearly indicating the tracking polarity may be omitted in theoptical disk.

In this embodiment, the second signal detecting section 410discriminates the values “0” and “1” based on a detection result on achange of the polarity of the differential signal 403. Alternatively, ifa crosstalk effect from an adjoining land track is significantly large,and it is difficult to detect a binary signal, address information, async pattern or the like within a predetermined time, or within apredetermined playback area, or within a predetermined retry processing,it is possible to extract an output signal solely from one of the twolight receiving areas of the photo-detector closer to the land trackfrom which data is to be played back, as the signal 403, in place ofusing a differential signal.

Further alternatively, the code detecting section 425 may output asignal requesting changeover of the tracking polarity to the trackingpolarity switching section 414 if it is difficult to detect a binarysignal, address information, a sync pattern or the like within apredetermined time, or within a predetermined playback area, or within apredetermined retry processing. In such an altered arrangement, sincethere is no need of detecting a code, a code for clearly indicating thetracking polarity may be omitted in the optical disk.

Further alternatively, it is possible to directly detect a change of adifferential signal, and to allow the code detecting section 425 tooutput, to the tracking polarity switching section 414, a signalrequesting changeover of the tracking polarity if the change is out of apredetermined range. In such an altered arrangement, since there is noneed of detecting a code, a code for clearly indicating the trackingpolarity may be omitted in the optical disk.

In the foregoing, described is the arrangement that the informationrecording/playback apparatus has the code detecting section 425 and thetracking polarity switching section 414. As shown in FIG. 10, theinformation recording/playback apparatus may be configured in such amanner that an integrated circuit 430 functionally has a code detectingsection 431 serving as code detecting means, and a tracking polarityswitching section 432 serving as tracking polarity switching means.Further alternatively, a computer program may functionally have the codedetecting section 431 and the tracking polarity switching section 432.

Next, another embodiment of the invention is described referring to FIG.11. FIG. 11 shows an optical disk 701, as another example of theinformation recording medium embodying the invention. The optical disk701 comprises a burst cutting area (BCA area) 705, a control data area702, and a data recording area 704, which are arranged in a radiallyoutward direction in this order. The control data area 702 is an area inwhich administration data and the like have been pre-recorded. The datarecording area 704 is an area in which data is recorded by a user. TheBCA area 705 is an area in which information for classifying thedisk-related contents recorded in the control data area 702 into furtherdetails has been recorded. The information recording into the BCA area705 is carried out by recording the information in the format of barcodein a factory after production of the optical disks. The informationrecording may be carried out in the same manner as information isrecorded in the data recording area 704, or may be carried out byutilizing a property change of a layer. Further alternatively, theinformation recording may be carried out by partly removing a layer bytrimming.

A code is recorded in the BCA area 705 to determine onto which track,namely, a groove track or a land track, tracking servo control isexecuted. For instance, the optical disk 701 is of a type, whereininformation is recorded on a land track 703.

FIG. 12 is a block diagram of another recording/playback apparatusembodying the invention. The recording/playback apparatus shown in FIG.12 can playback information recorded on the optical disk 701. Since therecording/playback apparatus shown in FIG. 12 has substantially asimilar arrangement as that of the recording/playback apparatus shown inFIG. 8, merely parts of the recording/playback apparatus shown in FIG.12 which are different from those of the recording/playback apparatusshown in FIG. 8 are described.

In the recording/playback apparatus shown in FIG. 12, a code detectingsection 425 functionally has a third signal detecting section 420serving as signal detecting means C, and a third pattern detectingsection 422 serving as pattern detecting means C, in addition to asecond signal detecting section 410 and a second pattern detectingsection 412. The third signal detecting section 420 receives a sumsignal 419 from an optical head 402 under focus servo control, andgenerates a binary signal 421 based on the sum signal 419. The sumsignal represents a sum of output signals from two light receiving areasof a photo-detector in the case where reflected light from the BCA area705 of the optical disk 701 has been received on the photo-detector,wherein the two light receiving areas are obtained by dividing the lightreceiving plane of the photo-detector into two halved parts along a lineparallel with a tangential line of the track direction. Sinceinformation has been recorded in the format of barcode in the BCA area705, the third signal detecting section 420 serving as the signaldetecting means C generates the binary signal 421 based on an intervalbetween bars of the barcode or the like.

Upon receiving the binary signal 421, the third pattern detectingsection 422 discriminates the code based on the binary signal 421outputted from the third signal detecting section 420, and outputs asignal 423 based on the discriminated code.

A tracking polarity switching section 414 receives the signal 423 fromthe third pattern detecting section 422, and outputs a signal indicatingwhether the tracking polarity is to be switched over based on the signal423.

In this section, described is a case that the optical disk 701 having aconfiguration that information is recorded on a land track is loaded inthe recording/playback apparatus. When the optical disk 701 is loaded,the optical head 402 travels to the BCA area 705 by a head movingsection 408. Focus servo control is executed onto the BCA area 705 inthis state by an unillustrated focus controlling section. When the focusservo control is executed, the optical head 402 receives reflected lightfrom the BCA area 705, and outputs a sum signal 419 to the third signaldetecting section 420 based on the reflected light. The third signaldetecting section 420 reads the information recorded in the format ofbarcode, which is constituted based on a judgment as to whether a layeris formed or not, or based on a difference in layer property, andgenerates a binary signal 421 based on the result of reading. The binarysignal 421 represents a value “0” or “1”, which is a combination of apredetermined number of cycles of time. For instance, as shown in FIG.11, a combination of cycles of time Ta, Tb, and Tc represents the value“0”.

The binary signal 421 is outputted to the third pattern detectingsection 422. The third pattern detecting section 422 retrieves the codebased on the binary signal 421, and outputs, to the tracking polarityswitching section 414, a signal 423 indicating that the trackingpolarity represents a land track. Then, the tracking polarity switchingsection 414 outputs, to a tracking controlling section 416, a signal 415requesting changeover of the tracking polarity, so that tracking servocontrol be executed onto the land track. Upon receiving the signal 415,the tracking controlling section 416 changes over the tracking servocontrol from the groove track to the land track, and executes trackingservo control onto the land track by monitoring a signal 418.

In the foregoing, described is the case that the code is provided in thecontrol data area or in the BCA area. Alternatively, the code may beprovided in either one of the areas constituting the optical disk, ormay be provided in all the areas constituting the optical disk.

As mentioned above, according to the embodiments of the invention, thecode for clearly indicating the tracking polarity representing the trackfrom which data is to be played back is provided both in the opticaldisk having a configuration that information is recorded on a groovetrack, and in the optical disk having a configuration that informationis recorded on a land track. In this arrangement, if the currentlydetected tracking polarity is not coincident with the polarityrepresenting the track used for playback, the tracking polarity can beswitched over by reproducing the code. This arrangement enables to keepthe time required for startup of the apparatus from unduly increasing.

In the playback method in accordance with the embodiment of theinvention, tracking servo control is executed according to thepredetermined polarity, and the code for clearly indicating the polarityrepresenting the track used for playback is reproduced. This arrangementenables to switch over the tracking polarity if the currently detectedtracking polarity is not coincident with the polarity representing thetrack used for playback, thereby keeping the time required for startupof the apparatus from unduly increasing.

In the playback method in accordance with the embodiment of theinvention, the tracking polarity can be switched over if it is difficultto detect a binary signal, address information, a sync pattern or thelike within a predetermined time, or within a predetermined area, orwithin a predetermined retry processing in executing tracking servocontrol in accordance with the predetermined polarity. This arrangementenables to keep the time required for startup of the apparatus fromunduly increasing.

BRIEF DESCRIPTION OF THE EMBODIMENTS

The embodiments of the invention are briefly described in the following.

(1) As mentioned above, in the embodiments, the code is provided in thecontrol data area.

(2) The code may preferably be provided in the data recording area.

(3) The code may be provided in the BCA area if the informationrecording medium has the BCA area in which data for classifying theinformation recording medium is recorded.

(4) Preferably, the code may be provided in each of recording layers ifthe information recording medium has the plural recording layers. Insuch an arrangement, the code can be generated in playback ofinformation recorded in any of the recording layers. This arrangementenables to keep the time required for startup of the recording/playbackapparatus from unduly increasing in playback of information recorded inthe information recording medium having the plural recording layers.

(5) Preferably, the code may be provided at such a position that thetracking servo control is executed prior to a code representing arecording condition.

(6) In the embodiments, the optical disk is of a recordable type.

(7) In the embodiments, the recording layer is formed by spin-coating,and information is recorded on the land track. The information recordingmedium having the above features is advantageous in shortening the timerequired for forming the recording layer, and in performing stableinformation recording while keeping the material cost of the informationrecording medium from unduly increasing.

(8) In the embodiments, the tracking polarity switcher switches over thetracking polarity if it is impossible to acquire the code in one of theconditions that an address information cannot be read, the code cannotbe read, a sync pattern cannot be detected, and a binary signalextracted from a differential signal obtained by tracking servo controlcannot be detected within a predetermined time, or within apredetermined area, or within a predetermined number of retries inexecuting the tracking servo control in accordance with a predeterminedpolarity. With this arrangement, the tracking servo control can besecurely executed onto the track in which information is recorded.

(9) According to the embodiments of the invention, in arecording/playback apparatus for performing at least one of recordinginformation onto a land track or onto a groove track of a recordinglayer of an information recording medium, and playback of informationrecorded on the land track or on the groove track, the apparatuscomprises an optical head, tracking servo controller for executingtracking servo control onto the land track or onto the groove track inthe information recording medium, and an integrated circuit.

(10) The tracking polarity may be switched over if it is impossible toacquire the code in one of the conditions that an address informationcannot be read, the code cannot be read, a sync pattern cannot bedetected, a binary signal extracted from a differential signal obtainedby tracking servo control cannot be detected, and the differentialsignal obtained by the tracking servo control is out of a predeterminedrange in executing the tracking servo control in accordance with apredetermined polarity.

(11) According to the embodiments of the integrated circuit forexecuting tracking servo control onto an information recording mediumhaving a land track and a groove track, the information recording mediummay have a code for indicating the groove track or the land track ontowhich the tracking servo control is executed, and the integrated circuitcomprises: code detector which controllably acquires the code inexecuting the tracking servo control in accordance with a predeterminedpolarity; and tracking polarity switcher which switches over a trackingpolarity representing the land track or the groove track if the codedetector judges it impossible to acquire the code within a predeterminedtime or within a predetermined number of retries.

In the above arrangement, since the tracking polarity is switched overbased on a result of controllably acquiring the code, the tracking servocontrol can be promptly executed onto the track in which information hasbeen recorded or is to be recorded. This arrangement enables to keep thetime required for startup of the recording/playback apparatus fromunduly increasing.

(12) According to the embodiments of the integrated circuit forexecuting tracking servo control onto an information recording mediumhaving a land track and a groove track, the integrated circuit maycomprise: tracking polarity switcher which switches over a trackingpolarity representing the land track or the groove track in executingthe tracking servo control in accordance with a predetermined polarityunder one of the following conditions that: a differential signalobtained by the tracking servo control is out of a predetermined range;a binary signal cannot be detected based on the differential signal; anda sync pattern cannot be detected within a predetermined time, or withina predetermined area, or within a predetermined number of retries.

In the above arrangement, even if the information recording medium doesnot have a code for indicating the groove track or the land track ontowhich tracking servo control is executed, the tracking servo control canbe promptly executed onto the track in which information has beenrecorded or is to be recorded. This arrangement enables to keep the timerequired for startup of the recording/playback apparatus from undulyincreasing.

(13) According to the embodiments of the computer program (computerprogram product) for causing a computer to function as a tracking servocontroller which executes tracking servo control onto an informationrecording medium having a land track and a groove track, the informationrecording medium may have a code for indicating the groove track or theland track onto which the tracking servo control is executed, and thecomputer program may comprise: code detector which controllably acquiresthe code in executing the tracking servo control in accordance with apredetermined polarity; and tracking polarity switcher which switchesover a tracking polarity representing the land track or the groove trackbased on a detection result by the code detector.

In the above arrangement, since the tracking polarity is switched overbased on a result of controllably acquiring the code, the tracking servocontrol can be promptly executed onto the track in which information hasbeen recorded or is to be recorded. This arrangement enables to keep thetime required for startup of the recording/playback apparatus fromunduly increasing.

(14) According to the embodiments of the computer program for causing acomputer to function as a tracking servo controller which executestracking servo control onto an information recording medium having aland track and a groove track, the computer program may comprise:tracking polarity switcher which switches over a tracking polarityrepresenting the land track or the groove track in executing thetracking servo control in accordance with a predetermined polarity underone of the following conditions that: a differential signal obtained bythe tracking servo control is out of a predetermined range; a binarysignal cannot be detected based on the differential signal; and a syncpattern cannot be detected within a predetermined time, or within apredetermined area, or within a predetermined number of retries.

(15) According to the embodiments of the information recording/playbackmethod for implementing at least one of recording of information onto aland track or onto a groove track of a recording layer of an informationrecording medium, and playback of information recorded on the land trackor on the groove track, the information recording medium may have a codefor indicating the groove track or the land track onto which trackingservo control is executed, and the method may comprise: switching over atracking polarity representing the land track or the groove track inexecuting the tracking servo control in accordance with a predeterminedpolarity if it is judged that the code cannot be acquired within apredetermined time or within a predetermined number of retries.

Since the above method comprises the step of switching over the trackingpolarity, the tracking servo control can be promptly executed onto thetrack in which information has been recorded or is to be recorded. Thisarrangement enables to keep the time required for startup of therecording/playback apparatus from unduly increasing.

(16) According to the embodiments of the information recording/playbackmethod for implementing at least one of recording of information onto aland track or onto a groove track of a recording layer of an informationrecording medium, and playback of information recorded on the land trackor on the groove track, the method may comprise: switching over atracking polarity representing the land track or the groove track inexecuting tracking servo control in accordance with a predeterminedpolarity under one of the following conditions that: a sync patterncannot be detected; a binary signal cannot be detected based on adifferential signal obtained by the tracking servo control; and thedifferential signal obtained by the tracking servo control is out of apredetermined range.

In the above arrangement, even if the information recording medium doesnot have a code for determining whether the tracking servo control isexecuted onto the land track or onto the groove track, the trackingservo control can be promptly executed onto the track in whichinformation has been recorded or is to be recorded. This arrangementenables to keep the time required for startup of the recording/playbackapparatus from unduly increasing.

(17) According to the embodiments of the information recording/playbackmethod for implementing at least one of recording of information onto aland track or onto a groove track of a recording layer of an informationrecording medium, and playback of information recorded on the land trackor on the groove track, the method may comprise: recording ofinformation onto the information recording medium or playback ofinformation recorded on the information recording medium is carried outin such a manner that directions of starting modulation of the track areopposite to each other with respect to a playback direction between theinformation recording medium having a configuration that tracking servocontrol is executed onto the land track, and the information recordingmedium having a configuration that the tracking servo control isexecuted onto the groove track.

According to the above method, the polarities of differential signalscan be made coincident with each other between the information recordingmedia, by utilizing optical characteristics of the information recordingmedia. This arrangement enables to read addresses of the informationrecording media with use of the same sequence, thereby keeping the timerequired for startup of the recording/playback apparatus from undulyincreasing.

(18) According to the embodiments of the information recording/playbackmethod for implementing at least one of recording of information onto aland track or onto a groove track of a recording layer of an informationrecording medium, and playback of information recorded on the land trackor on the groove track, the method may comprise: recording ofinformation onto the information recording medium or playback ofinformation recorded on the information recording medium is carried outin such a manner that directions of starting wobbling of the track areopposite to each other with respect to a playback direction between theinformation recording medium having a configuration that tracking servocontrol is executed onto the land track, and the information recordingmedium having a configuration that the tracking servo control isexecuted onto the groove track.

According to the above method, the polarities of differential signalscan be made coincident with each other between the information recordingmedia, by utilizing optical characteristics of the information recordingmedia. This arrangement enables to read addresses of the informationrecording media with use of the same sequence, thereby keeping the timerequired for startup of the recording/playback apparatus from undulyincreasing.

EXPLOITATION IN INDUSTRY

Since the present invention is useful in realizing prompt startup ofrecording/playback of information in or out of an optical disk, theinvention is applicable to an information recording medium, anintegrated circuit, a recording/playback apparatus, a computer program,and an information recording/playback method.

1. A method of manufacturing an information recording medium having arecording layer which has a groove track and a land track, such thatonly one of the land track and the groove track is to be selected as aninformation recording track of the recording layer, such thatinformation is to be recorded on only the selected one of the land trackand the groove track of the recording layer, and such that the one ofthe land track and the groove track onto which the information is to berecorded has a wobbled portion having address information, wherein theinformation recording medium includes a data area onto which theinformation is to be recorded, and includes a control data area ontowhich a recording condition for the information recording medium isrecorded, the control data area being concentrically located closer to acenter of the information recording medium than the data area, whereinthe wobbled portion includes a fundamental waveform signal having afundamental frequency, and the wobbled portion includes a signal that isdifferent from the fundamental frequency, wherein the signal that isdifferent from the fundamental frequency is added to or subtracted froma part of the fundamental waveform signal, so as to add the addressinformation to the wobbled portion, and wherein the method comprises:selecting the information recording track of the recording layer fromonly one of the land track and the groove track, so that the informationis only to be recorded onto the selected one of the land track and thegroove track of the recording layer; setting the wobbled portion of theinformation recording track, such that (i) a starting direction of awobble of the groove track of the recording layer, when the selectedinformation recording track is the groove track, and (ii) the startingdirection of the wobble of the land track of the recording layer, whenthe selected information recording track is the land track, are reversedirections of one another with respect to a reproduction direction, evenwhen same address information is recorded in the wobbled portion;forming the wobbled portion of the selected information recording trackaccording to the starting direction of the wobble of the set wobbledportion; and providing, in the control data area, a code indicating ontowhich of the groove track and the land track a tracking servo isexecuted, such that the code is provided at a forward position in thereproduction direction relative to an area of the control data areawhere the recording condition has been recorded.
 2. A method forrecording information onto and reproducing the information from aninformation recording medium having a recording layer which has a groovetrack and a land track, such that only one of the groove track and theland track is selected as an information recording track of therecording layer, such that the information is recorded onto only theselected one of the land track and the groove track of the recordinglayer, and such that the recorded information is reproduced from the oneof the land track and the groove track onto which the information isrecorded, wherein the information recording medium includes a data areaonto which the information is to be recorded, and includes a controldata area onto which a recording condition for the information recordingmedium is recorded, the control data area being concentrically locatedcloser to a center of the information recording medium than the dataarea, wherein the one of the land track and the groove track onto whichthe information is recorded has a wobbled portion having addressinformation, wherein the wobbled portion includes a fundamental waveformsignal having a fundamental frequency, and the wobbled portion includesa signal that is different from the fundamental frequency, wherein thesignal that is different from the fundamental frequency is added to orsubtracted from a part of the fundamental waveform signal, so as to addthe address information to the wobbled portion, wherein the one of theland track and the groove track onto which the information is recordedis identified as a selected information recording track of the recordinglayer, such that the selected information recording track of therecording layer is only one of the land track and the groove track, andsuch that the information is only recorded onto the selected one of theland track and the groove track identified as the selected informationrecording track of the recording layer, wherein the wobbled portion ofthe information recording track is set, such that (i) a startingdirection of a wobble of the groove track of the recording layer, whenthe selected information recording track is the groove track, and (ii)the starting direction of the wobble of the land track of the recordinglayer, when the selected information recording track is the land track,are reverse directions of one another with respect to a reproductiondirection, even when same address information is recorded in the wobbledportion, wherein the wobbled portion of the selected informationrecording track is formed according to the starting direction of thewobble of the set wobbled portion, wherein the information recordingmedium includes a code, in the control data area, indicating onto whichof the groove track and the land track a tracking servo is executed,such that the code is provided at a forward position in the reproductiondirection relative to an area of the control data area where therecording condition has been recorded, and wherein the method comprises:reproducing the code; and based on the reproduced code, performing atleast one of (i) recording the information only onto the one of the landtrack and the groove track selected as the selected informationrecording track, and (ii) reproducing the information only from the oneof the land track and the groove track selected as the selectedinformation recording track.